JP2858549B2 - Digital wireless communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital radio communication device divided into an outdoor device and an indoor device.
The present invention relates to an amplifier whose gain can be set and which is used for a reception signal amplifier circuit when an outdoor device and an indoor device are connected by only one cable.

[0002]

2. Description of the Related Art A conventional example of the present invention will be described with reference to the drawings.

FIG. 3 is a diagram showing a configuration of a conventional digital radio communication apparatus. In the figure, a transmitting-side indoor device 101 modulates an input digital signal and outputs the modulated signal as an IF signal to a transmitting-side outdoor device 102 via one coaxial cable 201.

The transmitting outdoor device 102 amplifies the digitally modulated IF signal to a predetermined level, and transmits a radio signal to the opposing receiving outdoor device 103.

[0005] The receiving-side outdoor device 103 converts the frequency of a radio (RF) signal received from the transmitting-side outdoor device 102 into an IF signal, amplifies the signal to a predetermined level, and then transmits the signal through a single coaxial cable 202. Output to the device 104.

[0006] The receiving-side indoor device 104 demodulates an output signal from the receiving-side outdoor device 103 to obtain output data.

The cable 201 is supplied with a transmission signal from the indoor device 101 on the transmitting side to the outdoor device 102 on the transmitting side and a power supply for the outdoor device 102 on the transmitting side. This can be sufficiently identified by using a high-frequency band filter or the like since the frequency difference between the two is large.

Similarly, a cable 202 is supplied with a reception signal from the reception-side outdoor device 202 to the reception-side indoor device 104 and a power supply for the reception-side outdoor device 103 from the reception-side indoor device 104.

FIG. 4 is a diagram showing a main configuration of the reception-side indoor device 104. In this figure, the components other than the demodulator 117 are connected to the cable 202 when the power supplied from the indoor device 104 on the receiving side is detected by the outdoor device 103 on the receiving side in order to amplify the level of the received signal attenuated by the cable 202. This is a circuit for setting the gain of the amplifier by using the voltage difference that has been dropped.

The voltage comparator 111 is connected to the outdoor device 10 on the receiving side.
3 and the receiving-side indoor device 1
The voltage information 12 detected at the input terminal 04 is compared to calculate a voltage difference, and the difference information 13 is output. For example, when the cable length between the receiving-side outdoor device 102 and the receiving-side indoor device 104 is long, the power supply voltage of the receiving-side outdoor device 103 has a large voltage drop due to the long cable, and the difference information 13
Becomes a large value.

Conversely, when the cable length between the two devices is short, the difference information 13 has a small value because the voltage drop due to the cable is small.

When a few seconds have passed since the power was turned on, the timer 116 outputs the timing pulse 17 to the amplification gain setting unit 11.
Output to 5

The amplification gain setting unit 115 includes a variable amplifier 113
, And gain setting information for controlling the gain. That is, when the difference voltage of the difference information 13 is large, the amplification gain setting unit 115 outputs the high gain setting information 14 and the difference information 1
When the value of 3 is small, small gain information 14 is output.

The setting information 14 sets the difference information 13 when the timing pulse 17 output from the timer 116 is input. Also, the difference information 13 is kept held by the latch circuit in the amplification gain setting unit 115 at that time.

The amplifier 113 can vary the degree of amplification according to the setting information 14. The amplifier 113 amplifies the received signal 15 sent from the outdoor device to a stable level, and amplifies the signal.
7 is output.

[0016]

The above-described amplification gain setting unit 115 sets the difference information by a timing pulse. The timing pulse for setting the gain is performed only once a few seconds after the power is turned on. Immediately after power-on, the current consumption of the receiving-side outdoor device 103 may not be stable. As a result, since the power supply voltage drop is different from that in the normal state, the set gain value of the amplifier is fixed at an inappropriate value, and there is a problem that the gain setting of the amplifier becomes an incorrect value.

As described above, the present invention solves the problem that the demodulation cannot be performed and the main signal does not conduct due to the mismatch of the received signal level due to an error in the gain setting of the amplifier. To provide.

[0018]

SUMMARY OF THE INVENTION The present invention relates to a digital wireless communication apparatus which is divided into an outdoor unit and an indoor unit. In the outdoor unit, the power supply voltage supplied from the indoor unit is monitored, and the voltage information is stored in the indoor unit. Means for transmitting to the indoor device, means for monitoring the power supply voltage supplied to the outdoor device, voltage information monitored by the indoor device, and voltage information monitored and sent by the outdoor device, In order to amplify the signal attenuated by the voltage comparator for calculating the difference and the cable connecting the outdoor device and the indoor device to a certain level, the amplification gain can be varied by gain information from the amplification gain setting device. A demodulator that outputs pull-in information indicating whether the amplifier and the amplified received signal are locked, and a voltage until the pull-in of the demodulator is established. Repeats the gain setting of the amplifier from, after established, it has an amplification gain setter to fix the gain setting value of the condition being retracted.

[0019]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a receiving-side indoor device 1 described with reference to FIG.
FIG. 14 is a diagram corresponding to the internal configuration of the system 04. Here, from the voltage drop amount of the power supply voltage detected by the indoor device as in the related art,
A gain setting protection function for setting the amplification gain of the amplifier 113 is provided.

The operations of the voltage comparator 111 and the amplifier 113 are the same as those shown in FIG.

4 is different from FIG. 4 in that the timer 116 is eliminated and the demodulator 114 causes the synchronization generated by the reason that the level of the reception signal 16 amplified by the amplifier 113 is too large or too small. The point is that the pull-in information 18 indicating the pull-in error is output to the amplification gain setting unit 112.

The amplification gain setting unit 112 receives the pull-in information 18 from the demodulator 114 and, when outputting a synchronization pull-in error, generates a predetermined clock pulse based on the synchronization pull-in error signal.

The input difference information 13 is updated for each clock pulse to obtain gain information 14. The value set by the amplification gain setting unit 112 is the same as that of the amplification gain setting unit 115 shown in FIG. Value. That is, FIG. 2 is a diagram illustrating a relationship between the difference information value and the setting information value.

In the figure, the difference information value and the setting information value have a linear relationship. As a result, difference information 1
When the value of 3 is large, it indicates that a long cable is used, and thus the setting information 14 for setting a high gain is set.
Is output, and when the value of the difference information 13 is small, it indicates that a short cable is used, so that the setting information 14 for setting a low gain is output.

When the pull-in error has disappeared, the amplification gain setting unit 112 continues to hold and output the setting information based on the difference information 13 immediately before the error disappears.

In the above-described embodiment, the method of obtaining the difference information 13 based on the pull-in error signal output of the demodulator 114 has been described. However, the present invention is not limited to this in order to solve the conventional problem.

That is, in the configuration shown in FIG. 4, the timer 116 is configured to output a timing pulse indicating that a few seconds have elapsed after the power was turned on. Can be solved after a sufficiently long time, e.g., about 30 minutes to 1 hour, elapses until is stabilized.

Although the embodiment of FIG. 1 shows a one-way transmission system for transmitting from the indoor device on the transmitting side and receiving at the indoor device on the receiving side, the present invention is not limited to this. With the function of the present invention, it goes without saying that the same effect can be obtained in bidirectional transmission.

[0030]

As described above, according to the present invention, it is possible to accurately set the gain by repeating the gain setting means of the amplifier for compensating the signal attenuation due to the cable length while the demodulator is not synchronized. This has the effect of setting the input signal level to an appropriate value and providing a highly reliable device.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is a graph of difference information versus setting information.

FIG. 3 is a block diagram of a digital wireless communication device.

FIG. 4 is a block diagram of a conventional gain setting.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Sending indoor apparatus 102 Sending outdoor apparatus 103 Receiving outdoor apparatus 104 Receiving indoor apparatus 111 Voltage comparator 112, 115 Amplification gain setting unit 113 Amplifier 114, 117 Demodulator 116 Timer 201, 202 Coaxial cable

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) H04B 3/00-3/18 H03G 3/30 H04Q 9/00

Claims (4)

(57) [Claims] 1. An indoor device and an outdoor device are connected by a single coaxial cable to transmit and receive a radio signal, and a power supply voltage is supplied from the indoor device to the outdoor device via the coaxial cable. In the digital wireless communication device, a voltage drop detecting unit that detects a voltage value dropped by the coaxial cable, and a synchronous pull-in of a demodulator by the coaxial cable obtained from an output of the voltage drop detecting unit, in a receiving unit of the indoor device. A digital wireless communication apparatus comprising: a gain varying unit that varies a gain at an input of the demodulator so as to compensate for attenuation of a received signal based on information. 2. The gain variable means includes means for compensating attenuation of a received signal based on said voltage value obtained by said voltage drop detecting means until synchronization of said demodulator is established. 2. The digital wireless communication apparatus according to claim 1, wherein the gain of the variable amplifier provided is controlled, and the gain in the pulled state is maintained after the synchronization is established. 3. An indoor device and an outdoor device are connected by a single coaxial cable to transmit and receive a radio signal, and a power supply voltage is supplied from the indoor device to the outdoor device via the coaxial cable. In the digital wireless communication device, the receiving unit of the indoor unit may include a voltage drop detecting unit that detects a voltage value dropped by the coaxial cable, and a predetermined timing pulse generated at power-on, wherein the voltage drop detecting unit A digital wireless communication apparatus comprising: a gain varying unit that reads an output and varies a gain at an input of the demodulator so as to compensate for attenuation of a received signal due to the synchronization cable. 4. The digital wireless communication apparatus according to claim 3, wherein the timing pulse is generated after a lapse of sufficient time until the outdoor apparatus becomes stable after power is turned on.